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        a:link{/*吧未被访问的链接选择出来*/
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        a:visited{/*把访问过的链接选择出来*/
            color:aquamarine;
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        a:hover{/*将鼠标经过的链接选择出来*/
            color:coral;
            text-decoration: underline;
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        a:active{/*选择鼠标按下还没有弹起的链接*/
            color:blue;
        }
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    <div><a href="#">呵呵呵哒</a></div>
    <div><a href="http://www.bahttp://www.baidu.com">未知网站</a > </div>
    
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